KR20150074296A - Non-oriented electrical steel sheet having superior magnetic permeability and method for manufacturing the same - Google Patents

Non-oriented electrical steel sheet having superior magnetic permeability and method for manufacturing the same Download PDF

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KR20150074296A
KR20150074296A KR1020130161719A KR20130161719A KR20150074296A KR 20150074296 A KR20150074296 A KR 20150074296A KR 1020130161719 A KR1020130161719 A KR 1020130161719A KR 20130161719 A KR20130161719 A KR 20130161719A KR 20150074296 A KR20150074296 A KR 20150074296A
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weight
less
steel sheet
annealing
oriented electrical
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KR1020130161719A
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Korean (ko)
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이세일
박준수
배병근
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주식회사 포스코
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Priority to KR1020130161719A priority Critical patent/KR20150074296A/en
Priority to CN201410706117.1A priority patent/CN104674136B/en
Publication of KR20150074296A publication Critical patent/KR20150074296A/en

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147—Alloys characterised by their composition
    • H01F1/14766—Fe-Si based alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C2202/00—Physical properties
    • C22C2202/02—Magnetic

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Dispersion Chemistry (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Manufacturing Of Steel Electrode Plates (AREA)
  • Soft Magnetic Materials (AREA)

Abstract

The present invention relates to a non-oriented electrical steel sheet and a method for manufacturing the same and, more specifically, to a non-oriented electrical steel sheet and a method for manufacturing the same, comprising: 1.5-4.0 wt% of Si; 0.01-0.50 wt% of Mn; 0.0005-0.02 wt% of Al; 0.001-0.15 wt% of P; 0.004 wt% or less of C (excluding 0 wt%); 0.0001-0.01 wt% of S; 0.003 wt% or less of N (excluding 0 wt%); 0.003 wt% or less of Ti (excluding 0 wt%); 0.01-0.15 wt% of Sn; and the remainder consisting of Fe and inevitable impurities. According to a non-oriented electrical steel sheet of the present invention, provided is a non-oriented electrical steel sheet having superior magnetic permeability.

Description

TECHNICAL FIELD [0001] The present invention relates to a non-oriented electrical steel sheet having a high magnetic permeability and a method of manufacturing the same. [0002]

The present invention relates to a non-oriented electrical steel sheet and a manufacturing method thereof. More particularly, the present invention relates to a non-oriented electrical steel sheet excellent in magnetic permeability and particularly improved in magnetic permeability at 1T and 1.5T, and a manufacturing method thereof.

The nonoriented electric steel sheet plays an important role in determining the energy efficiency of the electric equipment because the nonoriented electric steel sheet is used as an iron core material in rotating devices such as motors and generators and stationary devices such as small transformers, This is because it plays a role of converting it into mechanical energy.

The magnetic properties of the electric steel sheet include iron loss and magnetic flux density. The iron loss is energy loss, so the lower the better. On the other hand, when the magnetic permeability is high and the magnetic permeability is high, the same magnetic flux density can be obtained even when a smaller amount of current is applied. Therefore, it is possible to reduce heat loss caused by the coiled copper wire, .

Permeability values divided by 7 and the magnetic permeability of μ0 = 4π * 10 in a vacuum magnetic flux density of the magnetic flux density value (unit:: T) obtained at a given magnetizing force is evaluated by magnetizing given this value, the force (A / m unit) , And the larger this value is, the higher the magnetic flux density can be obtained with a smaller magnetizing force.

The iron loss, which is an important indicator of the nonoriented electric steel sheet, is a value indicating the energy loss due to magnetization. It is a factor that greatly affects the power efficiency of a stationary device such as a large transformer as well as a rotating device such as a motor. Especially when used in the authors' field, the iron loss will affect the overall efficiency of the device because the copper loss is small. However, in small motors such as small motors and small transformers used in the high magnetic field range up to 1.5T or more, copper loss may be as important or more important than iron loss. Therefore, it is necessary to use non-directional electric steel sheet which can reduce copper loss.

In order to improve the copper loss of the electric equipment, it is necessary to reduce the amount of current flowing through the coiled copper wire or reduce the length of the copper wire to reduce the heat loss caused by the electric resistance of the conductor when electricity flows. Therefore, various methods including reduction of impurities and improvement of grain size of the non-oriented electrical steel sheet used as an iron core material can be used as a method of obtaining a high magnetic flux density from a smaller magnetization force. Elements which reduce the iron loss induced by improving the resistivity of the steel sheet such as Si, Mn or Al and reduce the iron loss through this decrease the saturation magnetic flux density, so their use is limited in appliances with large copper loss.

In the inverter driven AC motors and the like, the electric steel sheet has a magnetic flux density of about 1.0 T so that magnetization occurs. Therefore, the magnetic permeability calculated through the magnetizing force to magnetize the vicinity of the electric steel sheet is highly correlated with the efficiency of the power transmission device. In addition, the W15 / 50 iron loss, which is conventionally used as an index indicating the magnetic characteristics of the non-oriented electrical steel sheet, is evaluated as energy loss when magnetized at a frequency of 50 Hz to 1.5 T, As an indicator, the magnetic permeability at this time also has an important meaning in a device driven in the high magnetic field region.

In order to improve the iron loss among the magnetic properties of the non-oriented electrical steel sheet, a method of adding an alloying element having a high specific resistance is generally used for increasing the electrical resistance. However, addition of an alloying element reduces the iron loss, but also decreases the magnetic flux density and permeability.

Therefore, in order to lower the core loss and improve the magnetic flux density and the magnetic permeability characteristic, a technique of using a clean steel having a very small amount of impurities or adding a trace alloy element such as Ti or V is used. However, all of these techniques raise the manufacturing cost and do not solve the problem that the magnetism is deteriorated due to the formation of fine precipitates.

Accordingly, an object of the present invention is to provide a non-oriented electrical steel sheet having low iron loss and high magnetic permeability and a method of manufacturing the same.

According to an aspect of the present invention,

0.001 to 0.15 wt.% Of P, 0.004 wt.% Or less (exclusive of 0 wt.%) Of C, 0.0001 to 0.04 wt.% Of Al, 0.01% by weight of S, 0.003% by weight or less (excluding 0% by weight) of N, 0.003% by weight or less (excluding 0% by weight) of Ti, 0.01 to 0.15% by weight of Sn, , And other unavoidable impurities.

According to one embodiment of the present invention, 0.15 wt% of 0.0001 to 0.15 wt% of Sb may be further included.

In the non-oriented electrical steel sheet, Al, Sn, Sb, and P satisfy the relations of [Al] <[Sn] + [Sb] and [Al] <[Sn] + [ , Where [Al], [Sn], [Sb], and [P] represent the contents of Al, Sn, Sb and P, respectively, in weight%.

In the non-oriented electrical steel sheet, Sn, Sb, and P may have a Sn content of 0.03 to 0.30, wherein Sn, Sb, [P] means that the content of Sn, Sb and P is represented by% by weight).

According to an embodiment of the present invention, the non-oriented electrical steel sheet may further contain 0.05 wt% or less of Cu, Ni, and Cr, and 0.01 wt% or less of Zr, Mo, and V, respectively.

Further, according to one embodiment of the present invention, a non-oriented electrical steel sheet having a thickness of 0.5 mm or less has a magnetic permeability at a magnetic flux density of 1.0 T and a 1.5 T sine wave at 50 Hz alternating current and a magnetic permeability of 10 and 15, When the magnetization in the direction perpendicular to the rolling direction is measured and averaged using a measuring device (SST), a condition of μ10 of 8000 or more and μ15 of 1800 or more can be satisfied.

Further, according to one embodiment of the present invention, an iron loss of not less than 0.5 mm or less in thickness is magnetized with a magnetic flux density of 1.0 T and a sine wave of 1.5 T in an alternating current of 50 Hz to W10 / 50 and W15 / 50 And the magnetic properties in the rolling direction and in the direction perpendicular to the rolling direction are averaged by using a measuring device (SST), the conditions of W10 / 50 of 1.5 W / kg or less and W15 / 50 of 4.0 W / kg or less can be satisfied.

According to an embodiment of the present invention, the non-oriented electrical steel sheet having a thickness of 0.35 mm or less is subjected to magnetic flux densities of 1.0 T and 1.5 T sinusoidal waves at 50 Hz alternating current for iron loss of W10 / 50 and W15 / 50 , And the magnetization in the rolling direction and in the direction perpendicular to the rolling direction are measured by using a measuring device (SST), and the W10 / 50 is 1.3 W / kg or less and the W15 / 50 is 3.0 W / kg or less.

According to another aspect of the present invention,

0.001 to 0.15 wt.% Of P, 0.004 wt.% Or less (exclusive of 0 wt.%) Of C, 0.0001 to 0.04 wt.% Of Al, 0.01% by weight of S, 0.003% by weight or less (excluding 0% by weight) of N, 0.003% by weight or less (excluding 0% by weight) of Ti, 0.01 to 0.15% by weight of Sn, Hot rolling the slab comprising the remainder of Fe and other unavoidable impurities to produce a steel sheet;

Annealing the hot-rolled steel sheet at 950 to 1200 占 폚;

Cold rolling the annealed steel sheet; And

And annealing the cold-rolled steel sheet at 950 to 1120 ° C, wherein the hot-rolled sheet annealing step and the final annealing step are performed at a temperature of less than 700 ° C for at least 1 second or more at 15 ° C or more per second And raising the temperature at a temperature raising rate of at least 10 ° C per second for at least one second at a temperature of 700 ° C or higher.

According to the non-oriented electrical steel sheet of the present invention, it is possible to provide a non-oriented electrical steel sheet having high permeability at 1T and 1.5T.

In addition, according to the present invention, the amount of addition of Al, Sn, Sb and P is controlled and the rate of temperature rise of the hot-rolled sheet annealing and the cold-rolled sheet annealing is controlled, Direction magnetic poles are averaged to W10 / 50 and W15 / 50 iron loss. When the magnetic permeability at this time is μ10 and μ15, μ10 is more than 8000 and μ15 is 1800 or more. .

The nonoriented electric steel sheet produced as described above can be used for a high efficiency AC motor, a high output small AC motor, an AC inverter motor, an iron core material for improving the efficiency and performance of a large transformer used in the author's field, As shown in FIG.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Hereinafter, the non-oriented electrical steel sheet of the present invention and its manufacturing method will be described in more detail.

The non-oriented electrical steel sheet of the present invention comprises 1.5 to 4.0 wt% of Si, 0.01 to 0.50 wt% of Mn, 0.0005 to 0.02 wt% of Al, 0.001 to 0.15 wt% of P, 0.004 wt% (Excluding 0% by weight) of C, 0.0001 to 0.01% by weight of S, 0.003% by weight or less (excluding 0% by weight) of N, 0.003% % Sn, and the balance of Fe and other unavoidable impurities.

Hereinafter, reasons for limiting each component and numerical value included in the non-oriented electrical steel sheet of the present invention will be described in accordance with an embodiment of the present invention.

First, the non-oriented electrical steel sheet of the present invention contains about 1.5 to about 4.0 wt% of Si.

Since Si is a component which increases the resistivity of steel and lowers the eddy loss in iron loss, it is difficult to obtain low iron loss characteristics at less than 1.5 wt%, and phase transformation occurs at annealing at 1000 DEG C or higher. . On the other hand, if it is added in an amount exceeding 4.0% by weight, it becomes extremely difficult to carry out the cold rolling. Therefore, in the present invention, the content of Si is limited to 1.5 to 4.0% by weight.

The non-oriented electrical steel sheet of the present invention contains about 0.01 to about 0.50 wt% Mn.

Since the Mn has the effect of increasing the specific resistance and lowering the iron loss in addition to Si and Al, the conventional unoriented electric steel sheet was attempted to improve the iron loss by adding at least 0.05 wt% of Mn. However, as the Mn addition amount increased, the saturation magnetic flux density The magnetic flux density at the time of application of a constant current decreases. Therefore, in order to improve the magnetic flux density and prevent the increase of iron loss due to inclusions, the amount of Mn is preferably limited to 0.01 to 0.50 wt%, more preferably 0.05 to 0.30 wt% to minimize the Mn content.

The non-oriented electrical steel sheet of the present invention contains 0.0005 to 0.02% by weight of Al.

Al is an element which is inevitably added for deoxidation of steel in a steelmaking process, and at least 0.01% by weight of Al is present in the steel in a general steelmaking process. However, when it is added in a large amount, the saturation magnetic flux density is decreased and fine AlN is formed to suppress the grain growth to lower the magnetic property, so it is limited to 0.0005 to 0.02 wt%, more preferably 0.01 wt% or less. That is, Al added as a non-resistive element forms a fine nitride, which causes magnetism to become dull. If the size of the article is small in the non-oriented electrical steel sheet, it will interfere with the movement of the magnetic wall and deteriorate the magnetism. Therefore, it is necessary to increase the frequency of formation of coarse inclusions.

Accordingly, the amount of Al added to the non-oriented electrical steel sheet of the present invention is adjusted to 0.0005 to 0.02% by weight, more preferably 0.0005 to 0.01% by weight, in the component system containing Si, Mn, Sn, Sb and P added thereto And controlling the S in the range of 0.0001 to 0.01% by weight to suppress the generation of inclusions such as fine AlN and MnS to improve the magnetic properties.

The non-oriented electrical steel sheet of the present invention contains 0.001 to 0.15% by weight of P.

The P decreases the iron loss by lowering the specific resistance and segregates in the grain boundaries to inhibit the formation of {111} texture which is harmful to the magnetism and forms {100} which is an advantageous aggregate structure. However, if it exceeds 0.15% By weight to 0.15% by weight. In addition, P is an element that lowers the surface energy of the {100} surface in the steel sheet surface, and the amount of P segregated on the surface is increased by containing the P content in a larger amount, thereby further lowering the surface energy of the {100} It is possible to improve the growth rate of crystal grains having a {100} face favorable to magnetism during annealing.

The non-oriented electrical steel sheet of the present invention contains not more than 0.004% by weight of C. However, 0 wt% is excluded.

When C is added heavily, it enlarges the austenite region and increases the phase transformation period. It suppresses the grain growth of ferrite during annealing and increases the iron loss. It combines with Ti and forms carbide to dislocate magnetism. , The iron loss is increased by magnetic aging at the time of use. Therefore, the content of C is limited to 0.004% by weight or less in the present invention.

The non-oriented electrical steel sheet of the present invention contains 0.0001 to 0.01% by weight of S.

S is an element which forms sulfides such as MnS, CuS and (Cu, Mn) S which are harmful to the magnetic properties, and therefore it is known that it is preferable to add S low to suppress an increase in iron loss. However, when S is segregated on the surface of the steel, it has the effect of lowering the surface energy of the {100} plane. Therefore, by adding S, a texture having strong {100} plane can be obtained. However, when it is added in an amount exceeding 0.01% by weight, the processability is largely lowered due to segregation of grain boundaries, and there is a problem such as coating due to surface segregation, so that the addition amount is limited as described above.

The non-oriented electrical steel sheet of the present invention contains 0.003% by weight or less of N. However, 0 wt% is excluded.

N is an element harmful to magnetism, such as nitrides being strongly bonded with Al, Ti or the like to inhibit crystal growth, and therefore it is preferable to contain N in a small amount. In the present invention, N is limited to 0.003 wt% or less.

The non-oriented electrical steel sheet of the present invention contains 0.003 wt% or less of Ti. However, 0 wt% is excluded.

Ti forms fine carbides and nitrides to inhibit crystal growth. As the amount of Ti is increased, the crystallinity is lowered due to increased carbides and nitrides, and the magnetism deteriorates. Therefore, the Ti content is limited to 0.003 wt% or less in the present invention.

According to an embodiment of the present invention, the non-oriented electrical steel sheet of the present invention contains 0.01 to 0.15% by weight of Sn.

Sn is added because it segregates in the grain boundaries and suppresses the diffusion of nitrogen through grain boundaries and improves the texture. If Sn is added in an amount of less than 0.01% by weight, the above effect can not be expected. If added in an amount exceeding 0.15% by weight, the Sn content is limited to 0.01 to 0.15% by weight since the rolling property is deteriorated.

The non-oriented electrical steel sheet of the present invention may further contain 0.0001 to 0.15% by weight or less of Sb.

Sb is an element to be added because it is segregated in grain boundaries and suppresses diffusion of nitrogen through grain boundaries and improves the texture. If it is contained in an amount of less than 0.0001% by weight, it is difficult to expect the effect. If it exceeds 0.15% by weight, The content of Sb is limited to 0.15% by weight or less.

According to an embodiment of the present invention, Sn, Sb and P in the composition may satisfy [Sn] + [Sb] + [P] of 0.03 to 0.30. Here, [Sn], [Sb] and [P] mean the content of Sn, Sb and P in terms of% by weight, respectively.

The Sn, Sb and P suppress the diffusion of nitrogen through the grain boundaries as a segregated element in the grain boundaries and control the grain growth rate during the final annealing, thereby helping to grow the grain favorable to the magnetism, Thereby imparting high magnetic flux density characteristics. When Sn, Sb and P are added in an amount exceeding 0.30% by weight, crystal grain growth is suppressed and iron loss is greatly increased, and the amount of precipitation is greatly increased to increase iron loss, The sum of the contents of Sn, Sb and P is limited to 0.03 to 0.30% by weight.

According to an embodiment of the present invention, Al, Sn, Sb and P can satisfy [Al] <[Sn] + [Sb] and [Al] <[Sn] + [P]. Here, [Al], [Sn], [Sb] and [P] mean the content of Al, Sn, Sb and P in terms of% by weight, respectively.

As described above, Al, Sn, Sb, and P satisfy the respective content ranges, and additionally, a synergistic effect in which the magnetism is further improved can be obtained when the content relationship between the elements is controlled to an appropriate range.

In addition to the above elements, Cu, Ni, and Cr may additionally include elements that are inevitably added in the steelmaking process. However, since Cu, Ni, and Cr react with impurity elements to form fine sulfides, carbides, and nitrides, Of the non-oriented electrical steel sheet, the content of Cu, Ni, and Cr is limited to 0.05 wt% or less, respectively.

It is preferable that Zr, Mo, and V are not added as they are strong carbonitride-forming elements. In the non-oriented electrical steel sheet of the present invention, the contents of Zr, Mo, and V are each 0.01% .

In addition to the above composition, the remainder is composed of Fe and other unavoidable impurities.

The non-oriented electrical steel sheet of the present invention may have a mu 10 of 8000 or more and a mu 15 of 1800 or more.

In this case, the non-directional electric steel sheet having a thickness of 0.5 mm or less was subjected to the measurement of the energy loss when the non-oriented electric steel sheet of the present invention was magnetized with a sine wave having magnetic flux densities of 1.0 T and 1.5 T at 50 Hz alternating current, W15 / 50, W15 / 50, W15 / 50, W15 / 50, and W15 / 50, respectively, and the permeability at this time is measured in the rolling direction and in the direction perpendicular to the rolling direction, The average value of the magnetic measurement values of the non-oriented electrical steel sheet of the invention can satisfy the condition that mu 10 is 8000 or more and mu 15 is 1800 or more.

In addition, the non-oriented electrical steel sheet of the present invention having a thickness of 0.5 mm or less may have a W10 / 50 of 1.5 W / kg or less and a W15 / 50 of 4.0 W / kg or less. In the nonoriented electrical steel sheet of the present invention having a thickness of 0.35 mm or less, W10 / 50 is 1.3 W / kg or less and W15 / 50 is 3.0 W / kg or less, kg and W15 / 50 is 2.3 W / kg or less.

The non-oriented electrical steel sheet of the present invention may be produced by a method for manufacturing an electrical steel sheet widely known in the technical field of the present invention.

In other words, according to another embodiment of the present invention, a method for producing a non-oriented electrical steel sheet according to the present invention comprises: 1.5 to 4.0% by weight of Si, 0.01 to 0.50% by weight of Mn, 0.0005 to 0.02% By weight of P, 0.004% by weight or less (excluding 0% by weight) of C, 0.0001 to 0.01% by weight of S, 0.003% by weight or less (excluding 0% (Excluding 0% by weight) of Ti, 0.01 to 0.15% by weight of Sn, and the balance of Fe, and other unavoidable impurities are hot-rolled to prepare a steel sheet;

Annealing the hot-rolled steel sheet at 950 to 1200 占 폚;

Cold rolling the annealed steel sheet; And

And annealing the cold-rolled steel sheet at 950 to 1120 ° C, wherein the hot-rolled sheet annealing step and the final annealing step are performed at a temperature of less than 700 ° C for at least 1 second or more at 15 ° C or more per second And the temperature is raised at a temperature raising rate of at least 10 ° C per second for at least one second at a temperature of 700 ° C or higher.

Hereinafter, a method of manufacturing the non-oriented electrical steel sheet of the present invention will be described in detail. Conditions not specifically described below shall be in accordance with normal conditions.

First, the non-oriented electrical steel sheet of the present invention comprises 1.5 to 4.0 wt% of Si, 0.01 to 0.50 wt% of Mn, 0.0005 to 0.02 wt% of Al, 0.001 to 0.15 wt% of P, 0.004 wt% (Excluding 0% by weight) of C, 0.0001 to 0.01% by weight of S, 0.003% by weight or less (excluding 0% by weight) of N, 0.003% By weight of Ti, 0.01 to 0.15% by weight of Sn, and the balance of Fe and other unavoidable impurities.

In addition, the slab may further contain 0.0001 to 0.15% by weight of Sb.

In the above slab, Al, Sn, Sb and P may be in the range of [Al] <[Sn] + [Sb] and [Al] <[Sn] + [ , [Sb] and [P] means that the contents of Al, Sn, Sb and P are represented by weight%, respectively.

Sn, Sb and P in the slab are preferably in the range of 0.03 to 0.30 wherein [Sn], [Sb] and [P] are the contents of Sn, Sb and P, respectively In terms of% by weight) can be satisfied.

The slab may further contain 0.05 wt% or less of Cu, Ni, and Cr, and 0.01 wt% or less of Zr, Mo, and V, respectively.

A more detailed description of the elements and contents contained in the slab is as described above in the non-oriented electrical steel sheet.

The non-oriented electrical steel slab formed as described above is reheated to about 1250 DEG C or less and then hot rolled. When the reheating temperature is higher than 1250 ° C., the precipitates such as AlN and MnS existing in the slab are reused after hot rolling to inhibit the grain growth and decrease the magnetism, so that the reheating temperature is limited to about 1250 or less.

Hot rolling is performed, and the hot rolled sheet is rolled up at about 750 캜 or less and cooled in air. The rolled hot-rolled sheet is subjected to hot-rolled sheet annealing, pickling, cold-rolling, and finally final cold-rolled sheet annealing.

The hot-rolled sheet annealing is annealing for magnetic improvement, and the hot-rolled sheet annealing temperature is about 950 to about 1200 ° C. If the annealing temperature of the hot-rolled sheet is lower than 950 ° C, the grain growth is insufficient. If the annealing temperature exceeds 1200 ° C, the crystal grains excessively grow and the surface defects of the plate become excessively excessive. Is set at 950 to 1200 ° C. The step of annealing the hot-rolled sheet can be performed within 5 minutes.

The hot rolled sheet picked up by a conventional method or the annealed hot rolled sheet is cold rolled.

The cold rolling is finally rolled to a thickness of 0.5 mm or less, and if necessary, it can be subjected to primary cold rolling and secondary cold rolling after intermediate annealing, and the final rolling reduction is in the range of 50 to 95%.

The final cold-rolled steel sheet is subjected to final cold-rolled sheet annealing. In the final annealing step for annealing the cold rolled sheet, the temperature of annealing of the cold rolled sheet during annealing is set at about 950 to about 1120 캜.

If the annealing temperature of the cold-rolled sheet is lower than 950 ° C, it is difficult to realize the process because of a long time required to obtain crystal grains of sufficient size to obtain low iron loss. At 1120 ° C or higher, The cold-rolled sheet has a cracking temperature of 950 to 1120 DEG C in one embodiment of the present invention since it may be finely precipitated during cooling after being re-used to adversely affect magnetism. The step of annealing the cold rolled sheet may be performed within 5 minutes.

Further, the cold rolling may be performed at least two times during the primary cold rolling or the intermediate annealing.

The hot-rolled sheet annealing step and the cold-rolled sheet annealing step are carried out at a temperature raising rate of not less than 15 ° C per second for at least one second to less than 700 ° C, and at least 10 ° C per second for at least one second at a temperature of 700 ° C or more.

If the temperature is continuously increased to 700 ° C. at a rate of increase of less than 15 ° C. per second, the recovery in the material excessively occurs, and the crystal grains upon recrystallization become finer and the annealing time becomes longer. At a temperature higher than 700 ° C., , It is difficult to obtain a fiber structure in which the {100} and {110} planes, which are preferable aggregates for magnetic properties, are parallel to the surface of the sheet at the time of recrystallization.

On the other hand, the average grain size of the steel sheet after annealing the cold rolled steel sheet may be about 30 to about 300 mu m.

The annealed sheet can be shipped after the insulating coating treatment. The insulating coating may be treated with an organic, inorganic and organic composite coating, or may be treated with other insulating coatings. The steel sheet can be used as it is after processing.

Hereinafter, a method of manufacturing a non-oriented electrical steel sheet according to the present invention will be described in detail with reference to examples. The following examples are illustrative of the present invention only and are not intended to limit the scope of the present invention.

<Examples>

Example  One

A slab having the composition shown in Table 1 was heated at 1150 占 폚, hot-rolled to a thickness of 2.5 mm, and wound at 650 占 폚. The hot-rolled steel sheet cooled in air was annealed at 1100 ° C for 3 minutes, pickled, cold-rolled to a thickness of 0.35 mm, and cold rolled sheet annealed at 1050 ° C for 1 minute to obtain a non-oriented electrical steel sheet.

Here, the temperature raising conditions in the step of annealing the hot-rolled sheet were changed to 16 ° C / s up to 700 ° C and to 13 ° C / s after 700 ° C. The temperature raising conditions in the step of annealing the cold rolled sheet were 20 ° C / s up to 700 ° C and 15 ° C / s after 700 ° C.

Example  2 to 7

A non-oriented electrical steel sheet was prepared in the same manner as in Example 1, except that the slab composition was changed.

Comparative Example  1 to 8

A non-oriented electrical steel sheet was prepared in the same manner as in Example 1, except that the slab composition was changed.

The compositions of Examples 1 to 7 and Comparative Examples 1 to 8 are shown in Table 1 below. The contents of C, S, N, and Ti not shown in Table 1 were 20 ± 5 ppm.

No. Si Mn P Al Sn Sb Example 1 2.5 0.15 0.01 <0.003 0.02 0.02 Example 2 2.5 0.15 0.05 0.005 0.03 - Example 3 2.5 0.25 0.05 0.004 0.05 0.01 Example 4 2.5 0.25 0.01 0.015 0.09 - Example 5 2.5 0.35 0.05 <0.003 0.05 0.01 Example 6 2 0.25 0.01 0.005 0.05 - Example 7 3 0.25 0.05 <0.003 0.05 - Comparative Example 1 2.5 0.35 0.01 0.05 0.02 - Comparative Example 2 2.5 0.25 0.01 0.5 0.03 - Comparative Example 3 2.5 0.15 0.05 0.78 - - Comparative Example 4 2.5 0.35 0.01 0.27 - - Comparative Example 5 2.5 0.15 0.01 0.45 0.03 0.03 Comparative Example 6 2.5 0.05 0.01 0.52 0.05 - Comparative Example 7 2.5 0.1 0.05 0.3 - 0.03 Comparative Example 8 2.5 0.15 0.01 0.12 0.08 -

In Table 1, the content units of Si, Mn, P, Al, Sn, and Sb are% by weight.

In the electrical steel sheets of Examples 1 to 7 and Comparative Examples 1 to 8, five or more specimens having a width of 6 cm and a length of 6 cm were obtained by accurately aligning the rolling direction and the rolling direction within 5 degrees. The W10 / 50, W15 / 50 iron loss and μ10 and μ15 magnetic permeabilities of the specimens were measured by the following method using a single plate magnetometer (SST). The results are shown in Table 2 below.

1) The iron loss (W 10/50, W 15/50) is the average loss (W / kg) in the rolling direction and the direction perpendicular to the rolling direction when the magnetic flux density in each 1.0Tesla and 1.5Tesla at 50Hz AC frequency organic.

2) The magnetic permeability (μ10, μ15) is the average permeability in the rolling direction and in the direction perpendicular to the rolling direction when magnetic flux densities of 1.0 Tesla and 1.5 Tesla are induced at 50 Hz frequency.

No. W10 / 50 W15 / 50 μ10 μ15 Example 1 One 2.07 9010 3350 Example 2 1.02 2.15 8540 3070 Example 3 1.03 2.09 8910 3410 Example 4 0.95 2.06 9270 3250 Example 5 One 2.11 8710 3170 Example 6 1.1 2.43 11520 4370 Example 7 0.83 1.94 8520 3120 Comparative Example 1 1.14 2.55 7010 1090 Comparative Example 2 1.09 2.41 7390 1210 Comparative Example 3 1.15 2.45 7130 980 Comparative Example 4 1.18 2.55 6950 950 Comparative Example 5 1.1 2.33 6900 1130 Comparative Example 6 1.09 2.33 7530 1250 Comparative Example 7 1.15 7090 1150 Comparative Example 8 1.04 2.23 8030 1450

As can be seen from Tables 1 and 2, in Comparative Examples 1 to 8, the content of Al exceeds 0.02% by weight, which is the upper limit of the present invention, and Comparative Examples 3 and 4 do not contain Sn, Out of conditions. These comparative examples exhibited low magnetic permeability characteristics of μ10 and μ15.

On the other hand, in the examples, the permeability of μ10 was more than 8000 and the permeability of μ15 was more than 1800, showing a very high permeability.

Example  8 to 10

Using the slab having the composition of Example 6, a non-oriented electrical steel sheet was produced by changing the conditions of the hot-rolled sheet annealing and the cold-rolled sheet annealing as shown in Table 3 below.

Comparative Example  9-12

Using the slab having the composition of Example 6, a non-oriented electrical steel sheet was produced by changing the conditions of the hot-rolled sheet annealing and the cold-rolled sheet annealing as shown in Table 3 below.

The conditions of the hot-rolled sheet annealing and the cold-rolled sheet annealing in Examples 8 to 10 and Comparative Examples 9 to 12 are shown in Table 3 below. The non-oriented electrical steel sheets produced by the respective manufacturing methods were measured for the magnetic permeability of 占 10 and the magnetic permeability of 占 5 by the following method and are shown in Table 3 below.

1) The magnetic permeability (μ10, μ15) is the average magnetic permeability in the rolling direction and in the direction perpendicular to the rolling direction when magnetic flux densities of 1.0 Tesla and 1.5 Tesla are induced at 50 Hz frequency.

2) The maximum temperature rise rate (℃ / s) shows the maximum temperature rise rate in at least one second under the graph of time-temperature rise at the corresponding temperature range.

No. Temperature below 700 ℃
Maximum heating rate for 1 second
(Unit: ° C / s) Temperatures above 700 ° C
Maximum heating rate for 1 second
(Unit: ° C / s) μ10 μ15 Hot-rolled plate
Annealing Cold-rolled sheet annealing Annealing of hot-rolled sheet Cold rolled plate
Annealing Example 8 16 20 13 15 11200 4130 Example 9 18 20 15 17 11000 3970 Example 10 15 25 13 20 11530 4210 Comparative Example 9 10 15 5 0.1 7300 1310 Comparative Example 10 13 16 3 3 6200 1150 Comparative Example 11 15 23 8 9 6500 1190 Comparative Example 12 15 20 14 5 6400 1195

As shown in Table 3, Examples 8 to 10 according to the production method of the present invention all exhibited a permeability of μ10 of 8000 or more and a permeability of μ15 of 1800 or more.

The annealing temperature of the hot-rolled sheet has a direct relationship with the efficiency in the actual production process, but it can be seen that there is a correlation with the magnetism as shown in Table 3 above. Especially, it is judged that it affects the magnetism according to the heating rate at 700 ° C or higher. In addition, the rate of temperature rise of the cold-rolled sheet is very important. Depending on the conditions of the manufacturing method of the present invention, the temperature raising rate at 700 ° C or higher has a large influence on the permeability. It is possible to obtain a non-oriented electrical steel sheet excellent in magnetic permeability when the temperature is raised and the temperature is raised to 10 ° C or more per second for at least 1 second at 700 ° C or more.

While the present invention has been described in connection with certain exemplary embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

Claims (20)

0.001 to 0.15 wt.% Of P, 0.004 wt.% Or less (exclusive of 0 wt.%) Of C, 0.0001 to 0.04 wt.% Of Al, 0.01% by weight of S, 0.003% by weight or less (excluding 0% by weight) of N, 0.003% by weight or less (excluding 0% by weight) of Ti, 0.01 to 0.15% by weight of Sn, And other unavoidable impurities.
The method according to claim 1,
[Al], [Sn], [Sb], and [P] are selected from the group consisting of [Al] <[Sn] + [Sb] [P] means that the content of Al, Sn, Sb and P is expressed in% by weight, respectively.
3. The method of claim 2,
Sn, Sb and P satisfy the relation of [Sn] + [Sb] + [P] in the range of 0.03 to 0.30 And the non-oriented electrical steel sheet satisfies the following formula (1).
The method of claim 3,
And further comprising 0.0001 to 0.15% by weight of Sb.
The method of claim 3,
Further comprising 0.05 wt% or less of Cu, Ni, and Cr, respectively.
6. The method of claim 5,
Zr, Mo, and V in an amount of 0.01 wt% or less, respectively.
The method according to claim 6,
And further comprising 0.0001 to 0.15% by weight of Sb.
8. The method according to any one of claims 1 to 7,
The non-oriented electrical steel sheet with a thickness of 0.5 mm or less has a magnetic permeability of 1.0 T and 1.5 T sine wave at 50 Hz alternating current, , The μ10 is 8000 or more and the μ15 is 1800 or more.
8. The method according to any one of claims 1 to 7,
For the nonoriented electric steel sheet having a thickness of 0.5 mm or less, the iron loss at the magnetic flux density of 1.0 T and 1.5 T sine wave at 50 Hz alternating current was set to W10 / 50 and W15 / 50, respectively, Oriented electric steel sheet having a W10 / 50 value of 1.5 W / kg or less and a W15 / 50 value of 4.0 W / kg or less when measured by a measuring machine (SST).
8. The method according to any one of claims 1 to 7,
The non-oriented electrical steel sheets having a thickness of 0.35 mm or less were subjected to magnetic flux densities of 1.0 T and 1.5 T sine waves at 50 Hz alternating current to give iron losses of W10 / 50 and W15 / 50, respectively, Oriented electric steel sheet having a W10 / 50 value of 1.3 W / kg or less and a W15 / 50 value of 3.0 W / kg or less when the average value is measured using a measuring machine (SST).
0.001 to 0.15 wt.% Of P, 0.004 wt.% Or less (exclusive of 0 wt.%) Of C, 0.0001 to 0.04 wt.% Of Al, 0.01% by weight of S, 0.003% by weight or less (excluding 0% by weight) of N, 0.003% by weight or less (excluding 0% by weight) of Ti, 0.01 to 0.15% by weight of Sn, And hot rolling a slab made of other unavoidable impurities to produce a steel sheet;
Annealing the hot-rolled steel sheet at 950 to 1200 占 폚;
Cold rolling the annealed steel sheet; And
Annealing the cold-rolled steel sheet at a temperature of 950 to 1120 ° C,
The step of annealing the hot-rolled sheet and the step of annealing the cold-rolled sheet may be performed at a temperature raising rate of 15 ° C or more per second for at least 1 second at a temperature of less than 700 ° C and at a temperature raising rate of 10 ° C or more per second for at least one second at a temperature of 700 ° C or more And the temperature of the non-oriented electrical steel sheet is raised.
12. The method of claim 11,
Al, Sn, Sb, and P are selected from the group consisting of [Al] <[Sn] + [Sb] and [Al] <[Sn] + [ ] And [P] means that the content of Al, Sn, Sb and P is expressed as% by weight, respectively.
13. The method of claim 12,
Sn, Sb and P satisfy the relation of [Sn] + [Sb] + [P] in the range of 0.03 to 0.30 % &Quot;)&lt; / RTI &gt; of the non-oriented electrical steel sheet.
14. The method of claim 13,
Wherein the slab further comprises 0.0001 to 0.15% by weight of Sb.
14. The method of claim 13,
Wherein the slab further comprises 0.05 wt% or less of Cu, Ni, and Cr, and 0.01 wt% or less of Zr, Mo, and V, respectively.
16. The method of claim 15,
Wherein the slab further comprises 0.0001 to 0.15% by weight of Sb.
17. The method according to any one of claims 11 to 16,
Wherein the step of annealing the hot-rolled sheet is performed within 5 minutes.
18. The method of claim 17,
Wherein the step of annealing the cold rolled sheet is performed within 5 minutes.
19. The method of claim 18,
Wherein the cold rolling step is performed at least two times with primary cold rolling or intermediate annealing interposed therebetween.
20. The method of claim 19,
Wherein the average grain size of the steel sheet after annealing the cold-rolled sheet is 30 to 300 占 퐉.
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* Cited by examiner, † Cited by third party
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KR20160078176A (en) * 2014-12-24 2016-07-04 주식회사 포스코 Non-orientied electrical steel sheet and method for manufacturing the same
WO2019132132A1 (en) * 2017-12-26 2019-07-04 주식회사 포스코 Non-oriented electrical steel sheet and method for preparing same
WO2024071628A1 (en) * 2022-09-30 2024-04-04 현대제철 주식회사 Non-oriented electrical steel sheet and manufacturing method therefor
WO2024106753A1 (en) * 2022-11-18 2024-05-23 주식회사 포스코 Non-oriented electrical steel sheet and manufacturing method therefor

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20160078176A (en) * 2014-12-24 2016-07-04 주식회사 포스코 Non-orientied electrical steel sheet and method for manufacturing the same
WO2019132132A1 (en) * 2017-12-26 2019-07-04 주식회사 포스코 Non-oriented electrical steel sheet and method for preparing same
US11492678B2 (en) 2017-12-26 2022-11-08 Posco Non-oriented electrical steel sheet and method for preparing same
WO2024071628A1 (en) * 2022-09-30 2024-04-04 현대제철 주식회사 Non-oriented electrical steel sheet and manufacturing method therefor
WO2024106753A1 (en) * 2022-11-18 2024-05-23 주식회사 포스코 Non-oriented electrical steel sheet and manufacturing method therefor

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